Colorimetric sensors are recognized as a promising means for target molecule detection as they provide rapid, cost-effective, and facile sensing visible to the naked eye. Challenges remain though in terms of their detection sensitivity and specificity for short-length target genes. Herein, we demonstrate the successful combination of the catalytic hairpin DNA assembly (CHA) approach with enzyme-linked immunosorbent assay (ELISA)-mimicking techniques for a simple, sensitive, and sequence-specific colorimetric assay to detect short SARS-CoV-2 target cDNA. In the developed CHA-based chemiluminescent assay, a low concentration of target cDNA is continuously recycled to amplify dimeric DNA probes from two biotinylated hairpin DNA until the hairpin DNA is completely consumed. The dimeric DNA probes are effectively immobilized in a neutravidin-coated microplate well and then capture neutravidin-conjugated horseradish peroxidase via biotin-neutravidin interactions, resulting in a sensitive and selective colorless-to-blue color change. The developed sensing system exhibits a high sensitivity with a detection limit of ~1 nM for target cDNA as well as the ability to precisely distinguish a single-base mismatched mutant gene within 2 h. As the proposed system does not require complex protocols or expensive equipment to amplify target cDNA, it has the potential to be utilized as a powerful tool to improve the detection sensitivity of target genes for clinical diagnostics with colorimetric detection.Brevetoxins (BTX) are pharmacologically active, lipid soluble cyclic polyether neurotoxins that are known to cause a wide range of neurological symptoms in humans.Harvesting and consumption of infected molluscs provide an entry point for BTXs into, the food chain, causing long-term health effects on accumulation for individuals, commonly in people with a compromised immune system and existing allergies. This study is an acoustic assay that has been constructed using a 9 MHz AT-cut quartz crystal resonator modified by attaching a specific single-stranded DNA aptamer. The DNA oligo modifies its conformation to attach itself to the binding site of the incoming BTX molecule resulting in a change in frequency on the QCR. A small Δf value was observed for lower concentrations of BTX indicating a small change in mass deposited on the crystal surface, while the opposite was true for higher concentrations. Cross-species behavior was evaluated using samples of similar origin, molecular weight and a combination of two toxins. The LOD of the fabricated QCR is 220 nM which is lower than the maximum recommended residue limit in food samples. Fresh mussel samples were spiked with known concentrations of BTX to evaluate its sensitivity in a food matrix. No interaction with other compounds was observed. Overall, this sensor finds potential application in the food sector (fishing units) where mussels are tested and graded for allergens and toxins before reaching the customer.Riboflavin and its derivatives are the most important coenzymes in vivo metabolism, and are closely related to life activities. In this paper, the first photolysis 129Xe biosensor was developed by combining cryptophane-A with riboflavin moiety, which showed photosensitivity recorded by hyperpolarized 129Xe NMR/MRI technology with an obvious chemical shift change of 5.3 ppm in aqueous solution. Cellular fluorescence imaging confirmed that the biosensor could be enriched in MCF-7 cells, and MTT assays confirmed that the cytotoxicity was enhanced after irradiation. Findings suggested that the biosensor has a potential application in tumor targeting and the inhibition of tumor cell proliferation after photodegradation.As a biomarker of several diseases, the activity of acid phosphatase (ACP) is generally used to assistantly diagnose these diseases. Thus, developing reliable ACP activity analytical methods becomes quite significant. Herein, we recommend a one-step sampling filtration-free electrochemical method for ACP activity determination based on the target-induced synergetic modulation of tag concentration and surface passivation. Mn3O4 microspheres with favorable oxidase-mimicking activity are synthesized to catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to its product TMBox, resulting in a remarkable re-reduction signal of TMBox to TMB recorded by an integrated electrochemical system consisting of screen-printed electrode (SPE) and 3D-printed holder. When hexametaphosphate ions (HMPi) with rich negative charges are employed to interact positively charged TMBox, the formed flocculent precipitate TMBox-HMPi automatically sedimentates onto SPE surface, and both the decreased concentration of free TMBox in solution and the increased electrode surface passivation triggered by TMBox-HMPi sedimentation synergistically reduce the re-reduction signal of TMBox. When ACP is present, it hydrolyzes the HMPi substrate, greatly relieving the formation of the TMBox-HMPi precipitate and its sedimentation onto SPE surface. As a result, the electrochemical re-reduction signal of TMBox becomes remarkable again. https://www.selleckchem.com/products/talabostat.html With the strategy of using one stimulus to generate two-fold signal change, highly sensitive ACP activity detection was realized, with a wide linear range from 0.05 to 50 U/L and a limit of detection down to 0.024 U/L. Reliable monitoring of ACP activity in clinical serum was also demonstrated.Carbon dots have been a promising nano-carbon material with many advantages, and attracted many more attentions. This study designed a new chemosensor integrating the strong fluorescent property of carbon dots and the magnetism of amino-functionalized magnetic core-shell nanomaterial, Fe@SiO2-NH2 for determination of 2,4,6-trinitrotoluene (TNT). In this system, fluorescent carbon dots interacted with amino groups on the surface of amino-functionalized magnetic core-shell nanomaterial leading to fluorescence quenching of carbon dots, appearance of TNT competitively replaced of carbon dots on the surface of the magnetic material through forming a Meisenheimer complex. This sensor exhibits excellent selectivity and sensitivity for TNT, and which provided a good dynamic linear range for TNT from 10 to 2000 ng mL-1. The experiments demonstrate a low detection limit of 2.15 ng mL-1. The intra-day precisions for 25, 100 and 500 ng mL-1 were 4.6, 2.3 and 0.5% (RSD, n = 6), inter-day precisions for 25, 100 and 500 ng mL-1 were 4.